Internal combustion kngine



g 9 L. M. WOOLSON 1,874,682

INTERNAL COMBUST ION ENGINE Filed July 21. 1930 B H? Y I 1 uttorncg llll 17 l 3 L r 1 L/ONEL M wooLso/waacmsw Patented Aug; aaisaz [UNITED STATES PATENT OFFICE from n. woonson, nncmsnn, urn or nanorr, meme, a! mum 1+. woonson, rxncurmx, or rnoonrmnn mean, moment, assumes. no mcxean moron can corrrm, or omens, momen a comma-101w or IICHIGAN mi'mmu. communion menu Application fled July :1, mo. mm no. new.

' This invention. relates to internal combustion engines, and more particularly to engines of the compression ignition t 1 In engines of this class, commonl known as Diesel engines, air is drawn into t e cy der andthen compressed to the point where,

its temperature rises sufliciently to automatically ignite the' fuel, which is forced into the cylinder while the air is thus compressed.

However, when such en 'nes are cold, or have been idling, or have een running upon low fuel supply, it sometimes happens, as

. they have been heretofore constructed, that the air when compressed will not reach a temperature which at all times will insure ignition. It is desirable therefore to have the air compression sufiicientl high to insure ignition under all conditions, but this leads to unnecessarily high pressureswhen the engine is working under full fuel charges.

The object of this invention, therefore, is to secure the high compression necessary for reliable ignition when the engine is starting or when idling, and yet avoid or overcome the unnecessarily high pressures produced when the engine is working with full fuel charges.

f varies with the fuel burned; so that, in a Stated in another way, the object of the invention is to vary the air compression ratio and the high load combustion pressure inversely with the temperature of the engine or of the cylinders thereof.

Another object of the invention is to vary the air compression ratio, and the high load combustion pressure, inversely with the temperature when the temperature has reached a definiteand fixed value.

In engines of the Diesel type, the amount of heat developed during operation, generally speaking, is proportional to the fuel burned. When the engine is running idly or on reduced load, the fuel required to keep the engine running is small. compared to that required when the engine is working under normal or heavy load. The temperature of the engine, and particularly of the cylinder and cooperating'parts, therefore broad sense, the temperature of these parts varies with the load, being lowest when the developed raises the general temperature of the engine, and this helps to raise the temrature of the air; so that, after the engine as heated up, it is not essential that the air compression shall be'as high as when the engine is starting or idling.

'ljhe inventor proposes to make use of the var ations in the thermal condition of the engine, and particularly of the cylinders thereof, to lower the air. compression ratio, as well as the high fuel combustion pressure, when the engine has acquired a definite and rather fixed temperature. To this end, the head of each cylinder is provided with a thermostat of the type which becomes active or effective upon a definite fixed rise in temperature. As here shown, this thermostat consists of a capsule or bellows, preferably of the form known inthe art as a sylphon ranged directly in the combustion chamber or in some auxiliary chamber communicating therewith, so as to vary the size of the combustion chamber in accordance with the temperature of the engine. By this means,-

when the temperature of the engine, or the cylinders thereof, attains a rather definite degree, depending upon the vaporizing point of the material in the e ansible element, the compensatingl piston 1s moved out to thereby enlarge t e clearance volume of the cylinder, thereby lowering both the air compression ratio and the high fuel combustion pressure.

Inasmuch as the air compression ratio of engines of this character is quite high, amounting to approximately 16 to 1 of the original volume of air, the space occupied by the air when thus compressed is quite I multiple cy inder en 'ne, intended more particularly for aerop ane use, although 1 menta small compared to the space initially occuditional space required.

The broad idea of varying. the air com; 'pression invergly with the engine tempera 'ture has beendisclosed, and mechanism for;- efi'ecting th' result duly claimed in, this inventors' ear erf application, serial No. 874,368, filed J 28, 1929; In that case the compression -ra i0 is varied by automatically varying the stroke of the pistons in their .,res ive cylinders, while the invention Whh forms the foundation of the present Iaflpplication is based upon the use of a thereach cylinder, or of some chamber supple to the cylinder, so that upon 0 r ation of the'thermostat the clearance vo ume or combustion space will be varied. By the use of,a thermostat which becomes effective upon a fixed rise in temperature, the clearance volume is enlarged only after this tem perature shall have been reached. 7

; Fi 1 is an end elevation of a multiple cylinfie r engine with the improvement embodied therein; and Y .i Fig. 2 is a vertical section. taken through oneof the cylinders, showingin detail one of the thermostatic devices attached thereto.

Referring to the drawin the character 10 indicates the crank case 0 an internal combustion' en 'ne, which, as here shown, is a of course this invention is not limited to that particular t case is a sha 12 rotatable in suitable bearings, not illustrated herein, and which may be of any preferred form, as for example, such as? those illustrated and described in this inventors earlier application, SerialNo.

374,368, above referred to.

Arranged around this crank case '10 are cylinders 17 of any desired number, .nine being shown in the engine here illustrated, and these cylinders are connected to the casing in 'any convenient way as by compression hoo 18. Within each cylinder is azpiston 1.9 0 usual construction. Pivotally connected to oneof these pistons is a pitmen 20, and to the others are similarly connected pitmen 21.,

The pitman '20 is what is usually termed a master pitman, and has a hub 22 secured rigidly'thereto or made integral therewith, and to this hub all of the other pitmen are pivotally connected, as by pins 23. The hub.

. .22 is mounted directly upon thewrist pin 24 cylinders and at the er is provided wi of engine. Within the crank nausea of the crank 511m 12, and serves to rotate 'the shaft in the usual way. One or more weights 25 of any preferred form serve to counterbalance the wrist in, the pistons and other movable parts. is arrangement of pistons cooperatin with a single crank shaft is old d we -1 known, an forms no artlof the present invention. The engine ere illustrated is of the four r iycle compression i ition type. Each cylina sing e air channel 26 and a single valve 27. Air is drawn into the cylinders throu h the air channels, and the products of com ustion escape therethrough;

the valves 27 thus serve both as inlet and outlet valves, and the channels 26 serve both to admit air and to discharge the products of combustion. Each valve 27 is 0 rated in any suitable way, as by a rocker 'ar 28 and actuating rod 29, working in-timed relation with the other elements of the engine, as is usual in engines of this character. responsive element in connection w1th Cooperating with each cylinder is a fuel and a pump 31. These nozzles and pumps .may be of any suitable construction, and

therefore are here illustratedonlydiagrammatically. The pum 8 must of course be connected to work in timed relation with the other parts of the engine; and it may. be said that it is'highly desirable that each pump shall be as close as ossible to its cooperating nozzle, so that fuel in desired variable quantities -from the pump through the nozzle into the cylinden Considering the operation as starting with the valve 27 open, movement of the piston down the cylinder draws air into the chamber. The valvejs then closed, and on the up stroke the air is compressed to the point where its temperature will ignite the fuel; the fuel is injected before the maximum compression, as is usual in engines of this character. The resulting combustion raises the pressure in the cylinder still higher and gives the piston its working stroke; just before the-piston reaches the end of its down stroke, the valve 27 is opened and the products of combustion allowed to esca the cylinder is substantially cleared o the products of combustion upon the up stroke of the piston. As the lston again moves'down, it draws fresh air may be injected directly into the cylinder, and the cycle of operation is repeated. y

The upper parts of the'several cylinders constitute the combustion chambers of the engine. Cooperating with these combustion determined tem represents piston therein, and 34 the thermostat for fixed to the this enlargement of the clearance volume or the combustion space takes place only after the temperature of the cylinders shall have reached a predetermined int; so that there will be no movement 0 the compensating pistons until this temperature is reached. 1

V Broadly speaking, the means for enlarging the combustion chamber consists of an auxiliary chamber which communicates withthe main cylinders; a movable wall or, piston, which is withdrawn more or less as the pre thermostat who becomes effective to move the piston at the proper time.

Thus-referring to the accompanying drawing, and particularly to Fig. 2 thereof, 32 the compensating cylinder, 33 the the piston. A piston rod 37 is piston. The piston normally rests upon a seat 38 around the opening in the top of the cylinder 17; and the thermostat rests upon a seat 39 formed in the cylinder 32.

The thermostat '34 contains a substance which will vaporize or boil when its cylinder operating working under full load attains the tempera ture determined upon, but which will not boil under the temperature produced by the engine when starting or idling or working upon minimum load.

The form of this thermostat is of the socalled sylphon type, wherein the walls are made of flexible material deeply corrugated so that it may elongate considerably under thewpressure produced within the chamber.

Any suitable material which will boil at the desired temperature may be used, as for instance water or alcohol. But this material 'is'illustrative only, and any other suitable substance may be used having a boiling point of approximately 200 Fahrenheit.

The expansible element of the thermostat as here illustrated is made annular in form but any other form may be employed. With the annular form, the piston rod 37 extends through the thermostat. The piston rod 37 carries at its upper end a disk 40, which rests upon the top of the thermostat 34.

Cooperating with the thermostat and auxiliary piston is a spring 43 having one end resting upon the disk 40 and the other bearing against the top 44 of the casing 45 which surrounds the thermostat and forms an extension of the cylinder 32. This spring should be of substantial resistance, so that it may hold the piston against movement due to the pressure produced when the engine is idling or working under low pressure. At such times, the thermostat is not operative, and the piston must be prevented from rising.

Moreover, the spring 43 must be of sufficient strength to prevent a rise of the auxiliary piston under the pressure "produced by the combustion .of full fuel charges. But it must be so designed that it will yield under rature is reached; and a the pressure produced by the thermostat or under the pressure of the-thermostat taken in connection with the combustion pressure. Therefore, as the temperature rises, the bellows or sylphon will expand under the pressure produced therein, and the thermostat alone, or the thermostat and the cylinder pressure combined, will lift the'piston 33,

thereby enlarging the combustion s ace or clearance volume ofthe cylinder. W en the cylinder cools, due to a lessening of the fuel c arges, the liquid in the thermostat will condense and the thermostat will contract;

and the atmospheric pressure on the outside of the thermostat together with the force of the spring will then cause the chamber to collapse, thereby permitting the spring to force the piston 33 to its seat, and thus re: strict the combustion space to that ofthe working cylinder alone.

To give some idea of the size of the compensatingcylinder relative to the working cylinder, it may be said that it need only be suflicient to increase the clearance volume or combustion space of the working cylinder by twenty or thirty per cent. Thus, in a cylinder of say four and a half inches in diameter, and a normal compression ratio of 16 to 1, it will be suflicient if this compression ratio can be reduced to 12 to 1, or approximately those figures. That is, the compensating cylinder and piston need only be sufficient to provide added space which amounts to twenty to thirty per cent more than the normal compression volume of the cylinder.

Thus, with a working cylinder of the size mentioned, and the compression ratio of 16 to 1, a compensating cylinder two inches in diameter, and a movement of the compensating piston of half an inch will be suflicient. These figures are merely illustrative, and

may be regarded as varying with. the needs 7 of each particular case.

It will be understood that various forms of I the invention other than those described above may be used without departing from the spirit or scope of the invention.

What is claimed is:' I

1. In an internal combustion engine, the combination of a combustion chamber, a pis ton therein, and means for varying the capacity of the chamber, said means being re- A combination 0 stat for varying the capacity of the chamber. 7

5. In an internal combustion engine, the combination of a combustion chamber a pis-. tontherein, a compensating piston therein, and a' thermostat operable during a predetermined temperature range in the chamber for. o crating .thecompensating piston to vary e capacity of the chamber in accordance with the tem erature.

6. In an. interna combustion engine, the combination of a combustion chamber, a piston therein, a compensating cylinder, a compgnsating piston therein, an expansible chamr containing a substance volatile upon predetermined rise in the temperature thereof for expanding thechamber and thus with,- drawing the compensating piston to enlarge the chamber when the temperature thereof exceeds a predetermined amount.

7. In an internal combustion engine, the combination of a cylinder, a piston therein, a'com nsating piston therein, a thermostat operab e during a predetermined temperature range in the chamber for operating the comensating piston, and a spring for restrainmg the piston;

In a com ression ignition engine, the g) a cylinder, 0, piston therein, a compensating piston therein, and a thermostat responsive during predetermined variations in the temperature of the cylinder for operating the compensating piston to vary the clearance volume of the cylinder combination of a directly with the temperature thereof and inversely with the air compression.

9. In a compression ignition engine, the combination 0 a cylinder, a piston therein, a compensating piston therein, a thermostat responsive during predetermined changes in temperature of the cylinder for operating the compensating piston to enlarge the clearance volume of the cylinder upon a predetermined rise in temperature thus decreasing the air compression ratio, and contracting the clearance volume upon a fall of the temperature. to a predetermined point thus increasing the air compression ratio.

10. In a compression ignition engine, the plurality of cylinders, a

der where for varyin y each cylinder governs its own 0 ration according to the requirements t ereof.

11. In an internal combustion engine, a plurality of cylinders, a piston for each cylinder, a compensating iston for each 0 linder, a thermostat for each cylinder operable durmfg a predetermined temperature range there- 0 for governing the compensating piston whereby the capacity of each cylinder an thereby the compression ratio is determined by the conditions of its own cylinder.

12. In a compression i ition engine, the combination of a plurahty of cylinders, a piston for each cylinder, a compensating cylinder'cooperating with each cylinder, a

the clearance volume of the cylini,

compensating piston in, each compensating cylinder, a sylphon containing a substance vaporizable at a predetermined temperature for actuating the compensating piston of its own cylinder, whereby the compression ratio is varied in accordance with the requirements of each cylinder.

13. The method of operating a compression ignition engine which consists in supplying an at a predetermined ratio of compression, su plying fuel according to the power require and varying the clearance volume of the engine in accordance with engine temperature.

14. The method of o sion ignition engine which consists in compressing the air to the maximum ratio when the. engine temperature is below a predetermined degree, supplying fuel to the engine and thermostatical f the combustion chamber an erebv the air compression ratio in accordance with the engine temperature when the en 'ne temperature is above the predetermin degree.

- In testimony whereof, I have hereunto subrating a compres-- y varying 11116 capacity 0 scribed my name this 17th da of Jul 1930.

EMMA F. ,OOL ON,, Ewembtrim of the Estate of Lionel M. W061- son, Deceased.

piston in each cylinder, a thermostat coopcrating with each cylinder and operable duringa predetermined range of temperature thereof. means cooperating with each cylinder and operated by the thermostat thereof 

